Molybdenum-vanadium bimetallic oxide catalyst and its application in chemical looping oxidative dehydrogenation of alkane

ABSTRACT

A molybdenum-vanadium bimetallic oxide catalyst and its application in the chemical looping oxidative dehydrogenation of alkane. The molecular formula of molybdenum-vanadium bimetallic oxide catalyst is MoVy and y represents the atomic molar ratio of vanadium and molybdenum. The supported MoVy catalyst is prepared by impregnation method, following the drying, calcination and tablet pressing. The reaction temperature was 450-550° C., and propane could be oxidized and dehydrogenated to propylene with high activity and selectivity, with propane conversion rate remaining at 30-40% and propylene selectivity at 80-90%. The fresh catalysts were reduced to the lower valence states with the lattice oxygen diffusion to propane. After the dehydrogenation, the reduced samples were regenerated to recover to the initial state and regain the lattice oxygen. During the redox cycles, the reaction performance remains stable, which can be used in the fixed bed reactor, moving bed reactor or circulating fluidized bed.

CROSS REFERENCE TO THE RELATED APPLICATIONS

This application is the national phase of International Application No. PCT/CN2018/096942, filed on Jul. 3, 2018, which is based upon and claims priority to Chinese Patent Application No. 201710672211.3, filed on Aug. 8, 2017, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This invention relates to a technology for the alkane dehydrogenation by metal oxides, and, more specifically, to a method and application of supported molybdenum-vanadium bimetallic oxides for the oxidative dehydrogenation of alkane to alkene.

BACKGROUND

As an important unconventional natural gas resource, shale gas is rich in low carbon alkanes. It is of great energy and environmental significance to convert the low carbon alkanes in shale gas into higher value chemical products. In recent years, the preparation of alkenes by dehydrogenation of alkanes has been fully developed.

Taking propane dehydrogenation to propylene as an example, the traditional non-oxidative dehydrogenation (PDH) technology uses a Cr or Pt based catalyst. Despite PDH being the commercial technology, it is strongly endothermic and operates at temperatures higher than 550° C. In contrast, oxidative dehydrogenation of propane (ODH) has the potential to improve the process efficiency for favorable thermodynamics and coking resistance. However, high C₃H₆ selectivity is hampered through consecutive oxygenation reactions. The direct mixing of hydrocarbons and gaseous oxygen also poses great safety concerns.

As an advanced and efficient thermochemical technology, chemical looping technology can realize near-zero-energy in-situ separation of products during the fuel transformation. Chemical looping oxidative dehydrogenation (CL-ODH) refers to the highly selective activation of propane to propylene by using the lattice oxygen in metal oxide (named as oxygen carrier). It does not only solve the influence of thermodynamic restriction in PDH, but also avoids the tendency of propane and propylene to oxidize deeply in the presence of molecular oxygen in ODH. The scheme of CL-ODH is shown in FIG. 1. Metal oxide catalysts are set up in fixed bed reactor. Gas switch system is set over the inlet pipe path to switch the fuel gas, inert gas and air gas. The fuel gas path is used to feed the low carbon alkane and inert gas path to the fixed bed reactor, which is used to purge the inert atmosphere to the inlet pipe path and the fixed bed reactor, so that the reaction can proceed under anaerobic conditions. An oxidized gas path is used to supply oxygen or air to a fixed bed reactor to regenerate a metal oxide catalyst.

At present, the oxygen carriers used in CL-ODH are mainly single-component metal oxides, including vanadium oxide, chromium oxide, tungsten oxide and so on. However, due to the influence of their own crystal structure, the lattice oxygen activity of these single metal oxides is affected by many factors, and cannot efficiently activate the C-H bond propane to produce propylene with high activity and selectivity. Therefore, how to regulate the oxygen activity of lattice by constructing composite metal oxides has important scientific and economic benefits. In the previous study, we applied for a catalyst for alkane dehydrogenation and a reaction device for fixed bed, moving bed and circulating fluidized bed. The catalyst in the invention is non-precious metal, non-toxic and harmless, and can be continuously regenerated in a reactor matched with the catalyst. While maintaining high catalytic activity, the selectivity of catalysts needs to be further improved.

SUMMARY

The purpose of this invention is to overcome the shortcomings of existing PDH technology, with the thermodynamic limit and the low efficiency, and provide a molybdenum-vanadium bimetal oxide catalyst and its application in chemical looping oxidative alkane dehydrogenation. The lattice oxygen from the Mo—V bimetal oxides can contribute to the activation of propane to react with hydrogen to generate water, effectively breaking the dynamic limitation and promoting the yield of propylene. Compared with the single vanadium oxide, the addition of Mo significantly inhibited the surface oxygen activity and increased the propane conversion and propylene selectivity.

The technical purpose of the invention is realized through the following technical scheme: the molybdenum-vanadium bimetallic oxide catalyst is a solid solution composed of molybdenum oxides and vanadium oxides. The molar ratio of metal Mo and metal V is 1:(4-30), and preferably 1:(6-18). Mo enters the volume phase lattice of V₂O₅, resulting in lattice distortion of V₂O₅ and forming molybdenum-vanadium solid solution. The catalyst is a supported catalyst and the support is Al₂O₃, TiO₂, SiO₂ or molecular sieve. The oxide mass percentage of molybdenum (molybdenum oxide mass/carrier mass) is 1-30%, preferably 10-20%. The oxide mass percentage of vanadium (molybdenum oxide mass/carrier mass) is 4-60%, preferably 40-60%. When preparing the samples, the steps are as follows:

Step 1, Ammonium metavadate and oxalic acid were evenly dispersed in deionized water, and then ammonium molybdate was added into the mixture according to the vanadium molybdate atomic ratio to form the dipping solution.

Step 2, The support is impregnated in the impregnation solution prepared in step 1 for equal volume impregnation;

Step 3, The support after the step 2 was dried at the temperature of 20 to 25 Celsius degrees for 8 to 12 h, then the support was transferred to be at 90° C. for 8-12 h. Finally, the samples were calcined under 500-600° C. for 2-4 h under air atmosphere, named as MoVy. y is the molar ratios of V and Mo.

In step 1, the mass ratio of oxalic acid to ammonium metavanadate is (2.8-3):(1.5-2).

In step 2, the support is Al₂O₃, TiO₂, SiO₂ or zeolites.

In step 3, the first drying temperature was at 20-25° C. for 10-12 h, then the samples were dried at 80-90° C. for 10-12 h, and calcined at 550-600° C. under air atmosphere for 2-4 h.

In step 3, molybdenum-vanadium bimetallic oxide catalyst powder was pressed into a granular catalyst of 20-40 meshes.

The invention is that the catalyst is operated in alkane dehydrogenation. The reaction is operated under anaerobic condition and the catalysts were used to supply the lattice oxygen to the alkane. As a result, the catalysts were reduced to a lower valence state and the alkane was oxidized to the alkene. The alkane is with at least one carbon atom, preferably including ethane, propane, n-butane, or isobutane. The low-valence catalysts react with the air or oxygen and is oxidized to the high-valence state recovering to the fresh states.

In the oxidative dehydrogenation reaction, fixed bed reactor, moving bed reactor or circulating fluidized bed is selected. The gas-solid two-phase contact mode (the gas-phase is mainly the raw material low-carbon alkane and the product low-carbon olefin, and the solid-phase is mainly the metal oxide oxygen carrier) mainly includes gas-solid countercurrent contact and gas-solid concurrent contact. In the process, the catalyst and quartz sand are evenly mixed for use, and the reaction is carried out under atmospheric pressure. The reaction temperature is 450-500° C. Nitrogen is injected to remove the oxygen and air, and then propane is injected. The weight hourly space velocity (WHSV) is 0.5-2 h⁻¹ and the propane volume percentage is 10-30%. The mass ratio of catalyst and quartz sand is (0.201):1, and preferably (0.5-0.8):1.

Compared with the present dehydrogenation technology, the invention has the following benefits:

(1) The catalysts in this invention are the supported Mo—V bimetallic oxides. Compared with single vanadium oxide, the selectivity of the alkene was obviously improved. Compared with molybdenum oxide, the conversion of the alkane is improved. By adjusting the ratio of molybdenum to vanadium, the optimal values of conversion and selectivity can be obtained.

(2) The catalysts were prepared by the impregnation method, having simple operation and low cost.

(3) The catalysts can maintain a high conversion rate and selectivity during the dehydrogenation period.

(4) After several redox cycles, the catalysts basically maintain the stability of structure and performance, and the conversion rate and selectivity remain basically unchanged.

(5) The catalyst during the regeneration period need ventilation with oxygen or air, on the one hand this operation can supply the lattice oxygen to the reduced catalysts. On the other hand, due to the exothermic reaction of carbon combustion, the released heat can be carried to the dehydrogenation reactor by the catalysts. by adjusting the mass weight of the catalysts, we can achieve the complete matching of heat during the dehydrogenation and reaeration reaction.

(6) The invention of the chemical looping alkane dehydrogenation compared with the present technology, the conversion of alkane and the selectivity of alkene is higher. In addition, the catalysts are non-noble and have low toxicity without the introduction of sulfide medium, leading to less harm to the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of the chemical looping oxidative dehydrogenation of propane.

FIG. 2 shows the activity test results of catalysts with different Mo additions.

FIG. 3 shows the activity test results of catalysts at different temperatures.

FIG. 4 shows the activity test results of catalysts at the different weight hourly space velocities (WHSV).

FIG. 5 shows the activity test results under different reaction times over VO_(x) and MoV₆ catalyst.

FIG. 6 shows the spectrum of H₂-TPR results of the fresh oxygen carrier (catalyst).

FIG. 7 shows the XRD results of the fresh oxygen carrier (catalyst).

FIG. 8 shows the cyclic stability results over MoV6.

FIG. 9 shows the structure analysis during redox cycles over MoV₆.

FIG. 10 shows the results of the lattice oxygen consumption over VO_(x) and MoV₆ under different reaction time. FIG. 11 shows the phase changes of VO_(x) and MoV₆ at different reaction time.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Firstly, the preparation of Mo—V bimetallic oxide catalyst was carried out, with each having a mass of 1 g. Meanwhile, single metal oxide catalyst of V and Mo was prepared, which was used for the comparison. The same preparation process parameters were selected for the preparation of three kinds of metal oxide catalysts.

EXAMPLE 1

Step 1: We dissolved 1.8 parts in mass of ammonium metabanadate (NH₄VO₃) and 2.9 parts in mass of oxalic acid (C₂H₂O₄) in 3 mL of deionized water. After the reaction was complete, we added a certain mass of ammonium molybdate ((NH₄)₆Mo₇O₂₄. 4H₂O) according to the atomic ratio between vanadium and molybdenum, and then, 2.0 parts in mass of Al₂O₃ were added in the above solution.

Step 2: the material obtained in step 1 was dried at 25° C. for 12 hours. Then the samples were dried at 70° C. for another 12 hours and finally calcined at 600° C. for 4 hours in air atmosphere. The molybdenum-vanadium bimetallic composite oxide supported on alumina was obtained, and its molecular formula was MoVy, where y is the moles of V relative to 1 mol Mo. y is equal to 6.

Step 3: The samples were grinded into the solid powder with a size of 20-40 mesh.

Step 4: Reactivity tests were performed in a quartz fixed-bed reactor with an internal diameter of 8 mm loaded with 500 mg catalysts (20-40 mesh) mixed with 1 mL of quartz particles with 20-40 meshes at atmospheric pressure. Switching between propane and air flows was employed during tests. The bed temperature was typically 500° C. and the samples were reduced using propane (4 mL/min) diluted in nitrogen (17 mL/min) at 1.4 atm. The weight hourly space velocity (WHSV) of propane was about 1 h⁻¹. The catalysts were then re-oxidized using air (15 mL/min). Between the reduction and re-oxidation reaction period, a purging period (17 mL/min of nitrogen) was introduced to prevent the mixing between propane and air. One redox cycle was completed. The stability test was carried out over MoV₆ for 100 continuous redox cycles. The time for reduction, re-oxidation and purging was set to 10 min, 15 min and 10 min. Exhaust streams were analyzed using an online gas chromatography (GC) (2060) equipped with a flame ionization detector (Chromosorb 102 column) and a thermal conductivity detector (Al₂O₃ Plot column). The instantaneous propane conversion, product selectivity and propylene productivity were calculated from Eq. (1) and Eq. (2) respectively:

Con(%)=100×([F _(C3H8)]_(inlet)−[F _(C3H8)]_(outlet))/[F _(C3H8)]_(inlet.)   (1)

Sel(%)=100×n _(i)×[F _(i)]_(outlet)/(Σn _(i)×[F _(i)]_(outlet))   (2)

Productivity=Con(%)×Sel(%)/10000×n _(i) /m   (3)

where i stands for different hydrocarbon products in exhaust gases, n_(i) is the number of carbon atoms of component i, and F_(i) is the corresponding molar flow rate. m is the weight of the vanadium oxides.

The accumulative conversion, selectivity and C₃H₆ yield were calculated from the GC data normalized to the amount of vanadium.

Yield=(∫Productivity dt)/N   (4)

Con(%)=(∫Con(%) dt)   (5)

Sel(%)=(∫Sel(%) dt)   (6)

where N is the amount of vanadium in vanadium redox oxides.

EXAMPLE 2

The reaction is carried out using the same method as in example 1. The difference is only that the mass of ammonium molybdate in step 1 is 0, and VO_(x) catalyst is obtained.

EXAMPLE 3

The reaction is carried out using the same method as in example 1. The difference is only that y in step 2 is 0, and MoO_(x) catalyst is obtained.

EXAMPLE 4

The reaction is carried out using the same method as in example 1. The difference is only that y in step 2 is 4.

EXAMPLE 5

The reaction is carried out using the same method as in example 1. The difference is only that y in step 2 is 9.

EXAMPLE 6

The reaction is carried out using the same method as in example 1. The difference is only that y in step 2 is 12.

EXAMPLE 7

The reaction is carried out using the same method as in example 1. The difference is only that y in step 2 is 18.

EXAMPLE 8

The reaction is carried out using the same method as in example 1. The difference is only that y in step 2 is 30.

EXAMPLE 9

The reaction is carried out using the same method as in example 1. The difference is only that the support in step 1 is SiO₂.

EXAMPLE 10

The reaction is carried out using the same method as in example 1. The difference is only that the support in step 1 is TiO₂.

EXAMPLE 11

The reaction is carried out using the same method as in example 1. The difference is only that the drying temperature in step 2 is 60° C.

EXAMPLE 12

The reaction is carried out using the same method as in example 1. The difference is only that the drying temperature in step 2 is 80° C.

EXAMPLE 13

The reaction is carried out using the same method as in example 1. The difference is only that the drying temperature in step 2 is 80° C.

EXAMPLE 14

The reaction is carried out using the same method as in example 1. The difference is only that the drying time in step 2 is 11 h.

EXAMPLE 15

The reaction is carried out using the same method as in example 1. The difference is only that the drying temperature in step 2 is 12 h.

EXAMPLE 16

The reaction is carried out using the same method as in example 1. The difference is only that the calcination temperature in step 2 is 500° C.

EXAMPLE 17

The reaction is carried out using the same method as in example 1. The difference is only that the calcination temperature in step 2 is 550° C.

EXAMPLE 18

The reaction is carried out using the same method as in example 1. The difference is only that the calcination time in step 2 is 3 h.

EXAMPLE 19

The reaction is carried out using the same method as in example 1. The difference is only that the calcination time in step 2 is 4 h.

EXAMPLE 20

The reaction is carried out using the same method as in example 1. The difference is only that the calcination temperature in step 4 is 450° C.

EXAMPLE 21

The reaction is carried out using the same method as in example 1. The difference is only that the calcination temperature in step 4 is 550° C.

EXAMPLE 22

The reaction is carried out using the same method as in example 1. The difference is only that the weight hourly space velocity (WHSV) of propane in step 4 is 0.5 h⁻¹.

EXAMPLE 23

The reaction is carried out using the same method as in example 1. The difference is only that the weight hourly space velocity (WHSV) of propane in step 4 is 2 h⁻¹.

The FIG. 2 shows that the addition of Mo improves the selectivity of propylene. However, excessive addition of Mo leads to the decreasing of propane conversion. As a result, the MoVO_(x) oxides (V/Mo=6) reaches 6.9 mol C₃H₆/kg-cat/h with 36% C₃H₈ conversion and 89% C₃H₆ selectivity at 500° C. and 1 h⁻¹ WHSV C₃H₈. Non-doped VO_(x) shows almost 17% CO_(x) selectivity with inhibited C₃H₆ selectivity of 79% at 500° C. and 1 h⁻¹ WHSV C₃H₈. Notably, pre-reduced VO_(x) shows lower C₃H₈ conversion (˜20%) via a PDH scheme. Pre-reduction by H₂ consumes the lattice oxygen, leading to the decrease of C₃H₈ conversion.

The FIG. 3 shows that a higher temperature benefits C₃H₈ conversion, whereas a higher temperature favors the C—C cleavage and the formation of CH₄.

The FIG. 4 shows that a lower space velocity would contribute to the CO_(x) selectivity and inhibiting propylene formation. The main reason is that the reduction of residence time will cause propane or propylene to be completely oxidized to CO_(x) by surface lattice oxygen with strong activity.

FIG. 5 shows that the conversion, selectivity and yield as a function of reaction time over MoV₆ at 500° C. and 1 h⁻¹ WHSV propane. With the increase of reaction time, the lattice oxygen is consumed gradually. In the initial reaction stage from 0 to 3 min, there is the highest lattice oxygen activity, leading to the highest propane conversion rate. However, the higher oxygen activity caused the overoxidation of propane or propylene to CO_(x). With the gradual depletion of surface lattice oxygen, the yield of C₃H₆ at 3-5 min reached the highest, indicating that the lattice oxygen from the bulk phase is the main reactive oxygen species that activates propane to produce propylene. At the end of the reaction range, from 10 to 15 min, the lattice oxygen is exhausted, and PDH dominated on the reduced VO_(x).

FIG. 6 shows that two obvious reduction peaks emerged in the H₂-TPR results, one related with OI diffusing at low temperatures and the other originated from OII diffusing at high temperatures. The OI species are responsible for overoxidation to CO_(x) and OII species are responsible for oxidative dehydrogenation for propylene. In addition, with the increase of Mo content, the reduction peak of OI species was gradually weakened, while the reduction peak of OII species was gradually increased, indicating that Mo addition indeed effectively regulated the activity of lattice oxygen species in oxygen carriers and inhibited the OI species with strong activity.

Moreover, with Mo addition, the FIG. 7 shows that the diffraction peaks of V₂O₅ (JCPDS 89-0611) become broader and shift, indicating the existence of lattice distortion or residual stress of V—O bonds. These characterization results have already been a sign for the formation of Mo—V solid solutions and the variations of V—O bonds with the doping of Mo.

The consumption of lattice oxygen leads to the decrease of propane conversion, and the regeneration is needed to regain the lattice oxygen. The redox stability test in FIG. 8 shows that the performance remains stable during the 100 redox cycles.

The FIG. 9 shows that the increasing diffraction intensity indicates the slight sintering of crystal particles and the favorable restoration of MoVO_(x) solid solutions in EDS mappings shows the excellent redox stability. Therefore, the sintering of catalysts could be inhibited due to the higher energy barrier of particle sintering than that of forming Mo—V solid solution through interphase diffusion. OI shows increase in weight after 50 redox cycles, which contributes to the increasing selectivity of CO_(x), indicating that anti-suppression of non-selective OI species may lead to the deactivation of MoVO_(x) solid solution. This also confirms that OI is responsible for over-oxidation, whereas the selective OII is positively related to the formation of propylene.

As shown in FIGS. 10 and 11, the left side is catalyst VO_(x), and the right side is catalyst MoV₆. The addition of Mo effectively reduces a large amount of lattice oxygen consumed by CO_(x) and increases the lattice oxygen consumed by oxidative dehydrogenation to propylene. With the increase of reaction time, the lattice oxygen diffusion from vanadium oxygen carriers to replenish the consumed oxygen leads to the submergence of crystalline V₂O₅ and gradually transforming to VO₂ and V₂O₃. Compared with VO_(x), MoVO_(x) shows a lower rate for the phase transformation. The reaction period follows overoxidation, oxidative dehydrogenation and non-oxidative dehydrogenation period.

The preparation parameters can be adjusted according to the contents of the invention, and the preparation of the catalyst and effective catalysis for propane can be realized. The above exemplary description of the invention should indicate that, without breaking away from the core of the invention, any simple deformation, modification or other equivalent replacement that can be made by technicians in the field without the cost of creative labor falls within the protection scope of the invention. 

1. A molybdenum-vanadium bimetallic oxide catalyst comprising a molar ratio of a metal Mo and a metal V is 1:(4-30) for a solid solution composed of a plurality of molybdenum oxides and a plurality of vanadium oxides, and the metal Mo enters a lattice of V₂O₅, resulting in a lattice distortion of V₂O₅ and forming a molybdenum-vanadium solid solution.
 2. The molybdenum-vanadium bimetallic oxide catalyst according to claim 1, wherein the preferred molar ratio of the metal Mo and the metal V is 1:(6-18).
 3. The molybdenum-vanadium bimetallic oxide catalyst according to claim 1, wherein the catalyst is a supported catalyst, and a support is Al₂O₃, TiO₂, SiO₂ or zeolites, a mass percentage of the molybdenum oxide is 1-30%, and a mass percentage of the vanadium oxide is 4-60%.
 4. The molybdenum-vanadium bimetallic oxide catalyst according to claim 3, wherein the mass percentage of the molybdenum oxide is 10-20% and the mass percentage of the vanadium oxide is 40-60%.
 5. A preparation method of a molybdenum-vanadium bimetallic oxide catalyst, the method comprising: step 1: evenly dispersing an ammonium metavadate and an oxalic acid in deionized water, and then adding an ammonium molybdate according to atom ratios of a vanadium and a molybdate to form a dipping solution; step 2, impregnating a support in the dipping solution prepared in the step 1 for an equal volume impregnation; step 3, after the step 2, drying the support at 20-25° C. for 8 to 12 h, then at 60-80° C. for 10-12 h and, finally, calcinating samples at 500-600° C. for 2-4 h under air atmosphere; wherein, a molecular formula of the molybdenum-vanadium bimetallic oxide catalyst is MoVy, where y represents a ratio of metal V and Mo.
 6. The preparation method of molybdenum-vanadium bimetallic oxide catalyst according to claim 5, wherein in the step 1, a mass ratio of the oxalic acid and the ammonium metavanadate is (2.8-3):(1.5-2).
 7. The preparation method of molybdenum-vanadium bimetallic oxide catalyst according to claim 5, wherein in the step 2, the support is Al₂O₃, TiO₂, SiO₂ or zeolites.
 8. The preparation method of molybdenum-vanadium bimetallic oxide catalyst according to claim 5, wherein in the step 3, the drying at 20-25° C. is performed for 10-12 h, and further comprises drying for 10-12 h at 80-90° C. before calcinating, at 500-600° C. for 2-4 h under air atmosphere.
 9. A method of chemical looping oxidative dehydrogenation of alkane, comprising: using the molybdenum-vanadium bimetallic oxide catalyst according to claim
 1. 10. The method of chemical looping oxidative dehydrogenation according to claim 9, wherein a reaction is under a plurality of anaerobic conditions and the molybdenum-vanadium bimetallic oxide catalyst serves as an oxygen carrier; wherein, the oxygen carrier reacts with a propane to produce a propylene and water to reduce the molybdenum-vanadium bimetallic oxide catalyst to a lower valence state.
 11. The method of chemical looping oxidative dehydrogenation according to claim 9, wherein the alkane is an ethane, a propane, an n-butane and/or an isobutene.
 12. The method of chemical looping oxidative dehydrogenation according to claim 9, wherein a gas-solid two-phase contact comprises countercurrent and concurrent contacts and a plurality of reactors comprises a fixed bed reactor, a moving bed reactor or a circulating fluidized bed reactor.
 13. The method of chemical looping oxidative dehydrogenation according to claim 10, wherein a lattice oxygen of the molybdenum-vanadium bimetallic oxide catalyst is involved in the reaction; and as the reaction progresses, the lattice oxygen is consumed gradually, reducing the catalyst activity; and a regeneration by air or oxygen to regain the lattice oxygen is provided.
 14. The method of chemical looping oxidative dehydrogenation according to claim 9, wherein the reaction is carried out under the atmospheric pressure at a reaction temperature of 450-550° C. using the molybdenum-vanadium bimetallic oxide catalyst and quartz sand mixture; a weight hourly space velocity (WHSV) of propane is 0.5-2 h⁻¹, and a propane volume percentage is 10-30%.
 15. The molybdenum-vanadium bimetallic oxide catalyst according to claim 2, wherein the catalyst is a supported catalyst, and a support is Al₂O₃, TiO₂, SiO₂ or zeolites, a mass percentage of the molybdenum oxide is 1-30%, and a mass percentage of the vanadium oxide is 4-60%.
 16. The method of chemical looping oxidative dehydrogenation according to claim 10, wherein the alkane is an ethane, a propane, an n-butane and/or an isobutene.
 17. The method of chemical looping oxidative dehydrogenation according to claim 10, wherein a gas-solid two-phase contact comprises countercurrent and concurrent contacts and a plurality of reactors comprises a fixed bed reactor, a moving bed reactor or a circulating fluidized bed reactor.
 18. The method of chemical looping oxidative dehydrogenation according to claim 10, wherein the reaction is carried out under the atmospheric pressure at a reaction temperature of 450-550° C. using the molybdenum-vanadium bimetallic oxide catalyst and quartz sand mixture; a weight hourly space velocity (WHSV) of propane is 0.5-2 h⁻¹, and a propane volume percentage is 10-30%. 